Vehicular camera with pcb focus tuning

ABSTRACT

A camera for a vehicular vision system includes a circuit board having a first surface and a second surface opposite the first surface. The circuit board has a first coefficient of thermal expansion (CTE). An imager is disposed at the first surface of the circuit board, and a lens assembly is at the imager. A bend-countering element is disposed at one of the first side and the second side of the circuit board. The bend-countering element has a second CTE that is different from the first CTE of the circuit board. The bend-countering element is selected so that, with the camera disposed at the vehicle, the bend-countering element counters temperature-induced bending of the circuit board to maintain focus of the lens assembly at the imager.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application claims priority of U.S. provisionalapplications, Ser. No. 62/711,657, filed Jul. 30, 2018, Ser. No.62/696,502, filed Jul. 11, 2018, and Ser. No. 62/690,527, filed Jun. 27,2018, which are hereby incorporated herein by reference in theirentireties.

FIELD OF THE INVENTION

The present invention relates generally to a vehicle vision system for avehicle and, more particularly, to a vehicle vision system that utilizesone or more cameras at a vehicle.

BACKGROUND OF THE INVENTION

Use of imaging sensors in vehicle imaging systems is common and known.Examples of such known systems are described in U.S. Pat. Nos.5,949,331; 5,670,935 and/or 5,550,677, which are hereby incorporatedherein by reference in their entireties. Various cameras have beenproposed for such imaging systems, including cameras of the typesdescribed in U.S. Pat. No. 7,965,336 and U.S. Publication No.US-2009-0244361, which are hereby incorporated herein by reference intheir entireties.

SUMMARY OF THE INVENTION

The present invention provides a driver assistance system or visionsystem or imaging system for a vehicle that utilizes one or more cameras(preferably one or more CMOS cameras) to capture image datarepresentative of images exterior of the vehicle, and provides abend-countering element disposed at a side or surface of the circuitboard, with the bend-countering element having a coefficient of thermalexpansion (CTE) that is different from the CTE of the circuit board.When the camera is disposed at the vehicle and exposed to a high or lowtemperature, the bend-countering element bends in an opposite directionthat the circuit board bends to at least partially counter the bendingof the circuit board so as to maintain focus of the camera or limit orreduce or minimize bending of the circuit board and over or underfocusing of the camera.

These and other objects, advantages, purposes and features of thepresent invention will become apparent upon review of the followingspecification in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view of a vehicle with a vision system thatincorporates multiple cameras;

FIG. 2 is a perspective view of a circuit board for a vehicular camera,showing an imager disposed at a surface of the circuit board;

FIG. 3 is a side view diagram of the circuit board and a lens of thecamera, showing the effects of exposure to high temperature;

FIG. 4 is another side view diagram of the circuit board and the lens ofthe camera, showing the effects of exposure to low temperature;

FIG. 5 is a perspective view of a circuit board for a vehicular camera,showing an imager disposed at a surface of the circuit board, withsolder strips disposed along the surface of the circuit board inaccordance with the present invention;

FIG. 6 is a side view diagram of the circuit board and the lens of thecamera, showing the effects of exposure to high temperature, which isopposite to the effects shown in FIG. 3;

FIG. 7 is a perspective view of a circuit board for a vehicular camera,showing an imager disposed at a surface of the circuit board, with a lowcoefficient of thermal expansion (CTE) plate disposed along the oppositesurface of the circuit board in accordance with the present invention;

FIG. 8 is a side view diagram of the circuit board and the lens of thecamera, showing the effects of exposure to high temperature, which isopposite to the effects shown in FIG. 3;

FIG. 9 is a perspective view of a circuit board for a vehicular camera,showing an imager disposed at a surface of the circuit board, with thecamera having active internal cooling and/or heating in accordance withthe present invention;

FIG. 10 is a side view diagram of the circuit board and the lens of thecamera, showing the effects of the active internal cooling duringexposure to high temperature, which reverses the bending of the circuitboard shown in FIG. 3;

FIG. 11 is a side view diagram of another camera, showing a differentCTE layer laminated or attached along a surface of the printed circuitboard;

FIG. 12 is a side view of a printed circuit board with layers of metaland isolation layers, and with an added layer having a different CTE;

FIG. 13 is a side view diagram of another camera, showing the housingwith angled PCB stands at the underside of the printed circuit boardsuch that expansion of the housing causes bending or flexing of theprinted circuit board; and

FIG. 14 is another side view diagram of another camera, showing thehousing with angled PCB stands at the imager side of the printed circuitboard.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

A vehicle vision system and/or driver assist system and/or objectdetection system and/or alert system operates to capture images exteriorof the vehicle and may process the captured image data to display imagesand to detect objects at or near the vehicle and in the predicted pathof the vehicle, such as to assist a driver of the vehicle in maneuveringthe vehicle in a rearward direction. The vision system includes an imageprocessor or image processing system that is operable to receive imagedata from one or more cameras and provide an output to a display devicefor displaying images representative of the captured image data.Optionally, the vision system may provide display, such as a rearviewdisplay or a top down or bird's eye or surround view display or thelike.

Referring now to the drawings and the illustrative embodiments depictedtherein, a vehicle 10 includes an imaging system or vision system 12that includes at least one exterior viewing imaging sensor or camera,such as a rearward viewing imaging sensor or camera 14 a (and the systemmay optionally include multiple exterior viewing imaging sensors orcameras, such as a forward viewing camera 14 b at the front (or at thewindshield) of the vehicle, and a sideward/rearward viewing camera 14 c,14 d at respective sides of the vehicle), which captures images exteriorof the vehicle, with the camera having a lens for focusing images at oronto an imaging array or imaging plane or imager or imaging device ofthe camera (FIG. 1). Optionally, a forward viewing camera may bedisposed at the windshield of the vehicle and view through thewindshield and forward of the vehicle, such as for a machine visionsystem (such as for traffic sign recognition, headlamp control,pedestrian detection, collision avoidance, lane marker detection and/orthe like). The vision system 12 includes a control or electronic controlunit (ECU) or processor 18 that is operable to process image datacaptured by the camera or cameras and may detect objects or the likeand/or provide displayed images at a display device 16 for viewing bythe driver of the vehicle (although shown in FIG. 1 as being part of orincorporated in or at an interior rearview mirror assembly 20 of thevehicle, the control and/or the display device may be disposed elsewhereat or in the vehicle). The data transfer or signal communication fromthe camera to the ECU may comprise any suitable data or communicationlink, such as a vehicle network bus or the like of the equipped vehicle.

The control unit may comprise or may be part of an autonomous vehiclecontrol system, whereby the cameras capture image data that is processedfor use in autonomously controlling the vehicle. Autonomous vehiclecameras may require very high levels of focus precision in allenvironments. Automotive cameras must maintain precise lens-to-imagerrelative position throughout the full range of operating temperatures.This is challenging because of the various camera assembly material CTEs(Coefficients of Thermal Expansion). The optical performance of the lensmay also be a contributor.

Simulations have been performed on the mechanical and optical design topredict changes as accurately as possible. The actual assembly willoften still have a five or more microns lens-to-imager shift due tounforeseen behaviors with the components and optics. Further long-termcontrol is often unachievable.

As can be seen with reference to FIGS. 2-4, a printed circuit board(PCB) 30 (such as one of the cameras 14 a-d) has a component 32 (such asan imager or imaging device or the like) disposed at a surface thereof(such as affixed at the surface of the PCB via solder balls 33 or thelike). The imager 32 comprises a component with a lower CTE (e.g., aceramic case sensor may have a CTE of less than 10 ppm/° C. (a unit ofchange in the part per degree Celsius), such as around 6 ppm/° C.) thanthe higher CTE of the PCB 30 (e.g., an FR4 substrate may have a CTE ofgreater than 10 ppm/° C., such as around 14 ppm/° C.). In FIG. 3, thePCB and imager are shown flexing or bending downward at the centerregion (between the side fixed points that are attached at a camerahousing 28) away from the lens 34 when the camera is exposed to highertemperatures. This is because the sensor expands less than the PCB inhigher temperature conditions, and results in the camera being underfocused. Similarly, and such as shown in FIG. 4, the PCB and imager areshown flexing or bending upward at the center region (between the sidefixed points that are attached at a camera housing) toward the lens 34when the camera is exposed to lower temperatures. This is because thePCB substrate expands less than the imager in lower temperatureconditions, and results in the camera being over focused.

The present invention offers ways to tune this shifting after the keycomponents in the optical path are designed and attached or fixedrelative to one another. The tuning or adjusting provides slight bendingof the imager printed circuit board (PCB) in a desirable direction andamount to accommodate or counter the flexing or bending that mayotherwise occur when the camera is exposed to extreme high or lowtemperature. The system or process may provide intentional tuning orbending of the PCB to achieve or maintain enhanced or ideal focus forthe particular camera configuration, whereby the PCB may be bent orflexed toward a planar configuration or toward a selected degree of bendto provide the ideal focus for the camera.

Thus, when the camera is disposed at the vehicle, the bend-counteringelement counters the temperature-induced bending of the circuit board(which may occur due to different CTEs between the imager and thecircuit board) to maintain focus of the lens assembly at the imager (sothat images imaged by the lens are focused at the image plane of theimager throughout a range of temperatures to which the camera isexposed). The bend-countering element is selected to correct for orcounter temperature-induced bending of the circuit board when the camerais exposed to high temperatures (such as, for example, temperaturesgreater than 40 degrees C. or greater than 60 degrees C. or greater than80 degrees C.), and/or low temperatures (such as, for example,temperatures below freezing, such as temperatures below 0 degrees C. orbelow −20 degrees C. or below −40 degrees C.). It is envisioned thataspects of the present invention may be applied to other types of highprecision sensors, such as Lidar or magnetic sensors or the like.

Referring now to FIGS. 5 and 6, one or more (such as two shown in FIG.5) solder strips 136 may be disposed at the surface of the PCB substrate130 (the same surface at which the imager 132 is disposed). The stripsof solder may be disposed on the front or back of the PCB as neededduring the SMT process (depending on the direction that the PCB is to bebent or curved). The provision of the solder strips can help bend thePCB as needed since the CTE of solder is higher (such as greater than 20ppm/° C., and such as, for example, about 22 ppm/° C.) than the PCBmaterial. Other types of materials, such as dispensed glue or othersuitable material having the desired or selected CTE (relative to theCTE of the PCB substrate material), may also be used for the samepurpose. As shown in FIG. 6, the PCB and imager are shown flexing orbending upward at the center region (between the side fixed points thatare attached at a camera housing) toward the lens 134 when the camera isexposed to higher temperatures (such as, for example, temperaturesgreater than 40 degrees C. or greater than 50 degrees C. or greater than60 degrees C.). This is because the solder expands more than the PCBsubstrate and the imager in lower temperature conditions. The type andamount of solder may be selected to cause the desired degree of bendingto counter the temperature-induced bending that would otherwise occur tothe PCB and imager. Optionally, solder strips may instead be applied toor disposed at the back side of the PCB substrate to bend the PCB in theopposite direction. The direction of bend and degree of bend (towardflat or toward a desired curvature to accommodate variations in thecamera at extreme temperatures) is dependent on the particular cameraconfiguration.

Optionally, and with reference to FIGS. 7 and 8, a CTE compensationplate 236 may be disposed at the PCB substrate 230 (at the side oppositefrom where the imager 232 is disposed), such as via solder balls 237 orthe like. The compensation plate 236 may comprise a metal plate with aCTE that is higher or lower than the PCB material (for example, a lowCTE plate (e.g., 410 stainless steel) may be soldered onto the PCB andmay have a CTE of less than 10 ppm/° C., such as about 9.9 ppm/° C.). Asshown in FIG. 8, the PCB and imager are shown flexing or bending upwardat the center region (between the side fixed points that are attached ata camera housing) toward the lens 234 when the camera is exposed tohigher temperatures. This is because the low CTE plate on the bottomexpands less than the PCB substrate in higher temperature conditions.Optionally, a higher CTE plate can be used to bend the PCB in theopposite direction to counter the temperature-induced bending of thePCB.

The compensation plate can be added to the back of the PCB to controlbending. The type and size of the plate may be selected to cause thedesired degree of bending to counter the bending that would otherwiseoccur to the PCB and imager. The size and material type will control theamount of bending. Optionally, the plate may be adhesively attached orsoldered or otherwise fastened to the PCB. Optionally, other types ofnon-solderable materials could be adhesively bonded or soldered orotherwise fastened to the PCB to control temperature-induced bending.Optionally, the plate or a frame element may be bonded or soldered orotherwise fastened at the imager side of the PCB to cause or controltemperature-induced bending of the PCB and imager in the oppositedirection.

Optionally, and with reference to FIGS. 9 and 10, an active internalheating device 336 may be disposed in the camera to actively heat thePCB substrate 330 (at the side opposite from where the imager 332 isdisposed). If a PCB has a tendency to bend with temperature change, theamount can be limited or controlled as desired if the PCB temperature isactively controlled. The heating device may comprise a thermal electricdevice (Peltier device) and can be used to either heat or cool the PCBas needed. The active internal cooling of the PCB by way of a thermalelectric cooler (TEC) can bring the assembly back to a condition wheredifferent CTEs have less impact. The thermal electric cooler can also berun in reverse to heat the PCB during cold conditions to maintainstability of the PCB and imager relative to the lens 334.

The thermal electric cooler or TEC may be operable to heat or coolselected components of the camera to take into account temperaturechanges and effects on various camera components (and may optionallyutilize aspects of the cameras described in U.S. patent application Ser.No. 16/364,250, filed Mar. 26, 2019 (Attorney Docket MAG04 P3563), whichis hereby incorporated herein by reference in its entirety). Optionally,the TEC may be actively controlled to change the focus of the cameraregardless of temperature variations and component expansion orcontraction due to extreme temperature changes. For example, the TEC mayheat or cool the imager circuit board (as discussed above) to move theimager relative to the lens to change the gap between the lens and theimager and thus to change the focus of the lens at the imager, or mayheat or cool one or more lens-to-imager positioning elements (thatretain the imager PCB relative to the lens to maintain focus of the lensat the imager) to change the gap between the lens and the imager andthus to change the focus of the lens at the imager or to maintain thefocus of the lens at the imager by countering temperature-inducedbending of the PCB.

The TEC thus provides an active focus or controllable focusing device,which may be operable to adjust the focus of the camera responsive to,for example, processing of image data captured by the camera (to bringthe images into sharper focus or to adjust focus to enhance focusing ofparticular elements present in the field of view of the camera or toprovide closer focus or more distant focus depending on the particularapplication or situation). For example, for a backup camera and during areversing maneuver of the vehicle, the system may adjust focusing of thecamera to closer objects responsive to detection of an object orpotential hazard immediately rearward of the vehicle, but may adjustfocusing of the camera to further objects or distances when no suchobjects or potential hazards are detected (to provide a clearer videodisplay of the region rearward of the vehicle for the driver to viewduring the reversing maneuver). Optionally, the TEC may provide such anactive focus feature responsive to a user input or responsive totemperature sensors or the like at the camera. Optionally, the TEC mayfunction to heat or cool other components of the camera that (whenheated/expanded or cooled/contracted) may affect the relative positionof the lens and imager and thus may affect the focus of the camera.

Optionally, the coefficient of thermal expansion (CTE) of variouscomponents (or strips or elements added to various components) may beselected such that the element(s) that the TEC heats/cools mayexpand/contract more or less than other components to achieve thedesired lens-to-imager adjustment. For example, materials with higher orlower CTEs may be selected to expand/contract more or less when the TECheats/cools, whereby the components work together to adjust the focus ofthe camera.

Therefore, the present invention provides for counter bending of the PCBand imager via use of different CTE materials or changing thetemperature of the PCB and imager. The different CTE materials functionto counter the bending of the PCB that may otherwise occur when thecamera is exposed to higher or lower temperatures. Optionally, thedifferent CTE materials may function to cause bending of the PCB toaccommodate other changes in the camera when exposed to higher or lowertemperatures. The camera of the present invention thus maintains focusor enhances focus by the lens at the imager or imaging device, andlimits or reduces over or under focusing when the camera is exposed toextreme temperatures. The enhanced focusing is achieved by intentionalbending of the PCB or bending of the PCB toward a flat or planar stateto counter temperature induced bending of the PCB that would otherwiseoccur when exposed to higher or lower temperatures.

Optionally, a laminate layer with different CTE properties may bedirectly added to the PCB at one side or may be embedded inside andbetween the layers of the laminated PCB substrate. Such a laminate layercauses the PCB substrate to reduce or even reverse temperature-inducedbending when the temperature changes. For example, and with reference toFIGS. 11 and 12, the PCB substrate 430 may comprise a plurality ofmetallic layers 430 a separated by respective isolation layers 430 b(such as, for example, layers of FR-4 glass-reinforced epoxy laminatematerial). As shown in FIGS. 11 and 12, an additional laminate layer 438is disposed at the side or surface of the PCB substrate 430 that isopposite from the side or surface of the PCB substrate where the imager432 is disposed or attached (such as via solder or the like).

By adding a layer of laminate material to one side of PCB, when theadded layer has a lower CTE than the PCB's CTE, the PCB will bend due tothe mis-match of CTEs. As can be seen with reference to FIG. 12, when acamera (without the added layer or other different CTE elements) isexposed to higher temperatures, the PCB substrate expands more than theimager and causes flexing or bending such that the imager is underfocused (such as also shown in FIG. 3), but with the added layer 438laminated or disposed at the opposite side of the PCB 430 from theimager 432, the layer (having a lower CTE than that of the PCB) controlsor limits or reduces temperature-induced flexing or bending of the PCBand imager to maintain the desired or set focus for the imager 432 andlens 434.

The added laminate layer material may comprise, for example, a metalcore (e.g., copper-invar-copper (CIC) or copper-molybdenum-copper (CMC),with a CTE of about 8 ppm/° C. or about 6 ppm/° C., respectively), or aKevlar Thermount or Aramid laminate. A commonly used FR-4 PCB has a CTEof about 15 ppm/° C. The bending amount can be controlled and tuned byusing different material (materials above are some examples) for theadded layer.

Optionally, the added layer may be disposed at the imager side of thePCB. If the added layer is placed at the opposite side or imager side ofthe PCB, the PCB will bend to the opposite direction. The added layercan also be placed inside the PCB substrate, such as between thelaminated layers of the substrate to control the amount of the PCBbending, since the position of the added layer (with different CTE) atthe substrate effects the degree of bending it causes. For example, thecloser to the center of the PCB that the added layer is disposed, theless bending it causes.

Optionally, more than one added layer (having a lower CTE than that ofthe other layers of the PCB substrate) may be added at the PCB substratewhen the layers are separated by one or more metal conducting layers.These multiple low CTE layers can increase the PCB bending controleffect. Optionally, the camera may utilize one or more layers with alarger CTE (than that of the other layers of the PCB substrate) at thePCB but at the opposite side of the PCB to achieve the same PCB bendingcontrol effect.

Optionally, the camera housing may be designed to assist in controllingflexing or bending of the PCB and imager relative to the lens. Forexample, and with reference to FIG. 13, the PCB 530 may be attached(such as via adhesive or fasteners or screws or the like) at the camerahousing 528 at two or more angled stands or stanchions or posts 540 ofthe housing. In the illustrated embodiment of FIG. 13, the stanchions540 are at the opposite side of the PCB 530 from the imager 532, suchthat, when the camera is exposed to higher temperatures, the plastichousing 528 expands more than the PCB, such that the PCB stands tiltmore and bend the PCB and imager away from the lens 534 (which isattached at the camera housing 528 via adhesive 535 or the like) so thatthe imager is under focused at the lens 534. Optionally, and such asshown in FIG. 14, the stanchions 540′ are at the same side of the PCB530 as the imager 532, such that, when the camera is exposed to highertemperatures, the plastic housing 528′ expands more than the PCB, suchthat the PCB stands tilt more and bend the PCB and imager toward thelens 534 so that the imager is over focused at the lens 534.

The adjustable PCB stands (such as two or four stands or stanchions orbosses or any number of stands or stanchions or bosses) that support thePCB at rear side or front side of the PCB and that attach to the PCBthrough screws or glue, control PCB bending when the temperaturechanges. This is because the plastic housing expands more than the PCBas the temperature rises, such that the stands or stanchions tilt andbend the PCB and imager as the temperature rises. Typically, the CTE ofthe PCB is smaller or less than the CTE of the plastic housing material,or bigger or larger than the CTE of the metal housing material. When thetemperature changes, the PCB and the housing expand or contract indifferent amounts and thus cause the PCB to bend and cause the imager tomove away from the lens focal plane such that the camera loses focussharpness. The different height of the PCB stands can cause differentPCB bending amounts (as taller PCB stands cause less PCB bending due tothe smaller tangential forces applied to the PCB). If the height of thePCB stands are changeable in design, the PCB can bend in differentamounts and/or in different direction by design to cancel or reducefocus movement caused by other elements (e.g., the lens focal planemoves and glue height changes during temperature changes).

As shown in FIG. 13, the PCB stands may protrude from the rear housingand engage the PCB at its rear side, which bends the PCB and moves theimager further away from lens when the temperature rises. As shown inFIG. 14, the PCB stands may protrude from the front part of the housingand engage the PCB at its front or imager side, which bends the PCB andmoves the imager closer toward lens when the temperature rises. As canbe seen with reference to FIGS. 13 and 14, the height of the PCB stands540, 540′ can be adjusted by moving up or down from the plateau (therear or front of the housing) that supports the PCB stand. Such a heightadjustment of the stands or stanchions (and thus an adjustment of thedegree of bending of the PCB as the temperature rises) can be arelatively simple change to the housing injection molding tools after acamera sample is tested and the amount of desired PCB bending change isknown. Thus, various sizes of the stands or stanchions can be tested anda particular size (including length and cross dimension and/or shape)stand or stanchion can be selected to provide the desired or appropriatedegree of bending of the PCB to effectively counter thetemperature-induced bending of the PCB when the camera is exposed toextreme temperatures above or below a nominal range of temperatures(such as between about 0 degrees C. and about 40 degrees C. orthereabouts).

The camera module may utilize aspects of the cameras and connectorsdescribed in U.S. Pat. Nos. 9,621,769; 9,277,104; 9,077,098; 8,994,878;8,542,451 and/or 7,965,336, and/or U.S. Publication Nos.US-2009-0244361; US-2013-0242099; US-2014-0373345; US-2015-0124098;US-2015-0222795; US-2015-0327398; US-2016-0243987; US-2016-0268716;US-2016-0286103; US-2016-0037028; US-2017-0054881; US-2017-0133811;US-2017-0201661; US-2017-0280034; US-2017-0295306; US-2017-0302829;US-2018-0098033; US-2019-0121051; US-2019-0124238 and/orUS-2019-0124243, which are hereby incorporated herein by reference intheir entireties.

The imaging sensor or camera may capture image data for image processingand may comprise any suitable camera or sensing device, such as, forexample, a two dimensional array of a plurality of photosensor elementsarranged in at least 640 columns and 480 rows (at least a 640×480imaging array, such as a megapixel imaging array or the like), with arespective lens focusing images onto respective portions of the array.The photosensor array may comprise a plurality of photosensor elementsarranged in a photosensor array having rows and columns. Preferably, theimaging array has at least 300,000 photosensor elements or pixels, morepreferably at least 500,000 photosensor elements or pixels and morepreferably at least 1 million photosensor elements or pixels. Theimaging array may capture color image data, such as via spectralfiltering at the array, such as via an RGB (red, green and blue) filteror via a red/red complement filter or such as via an RCC (red, clear,clear) filter or the like. The logic and control circuit of the imagingsensor may function in any known manner, and the image processing andalgorithmic processing may comprise any suitable means for processingthe images and/or image data.

For example, the vision system and/or processing and/or camera and/orcircuitry may utilize aspects described in U.S. Pat. Nos. 9,233,641;9,146,898; 9,174,574; 9,090,234; 9,077,098; 8,818,042; 8,886,401;9,077,962; 9,068,390; 9,140,789; 9,092,986; 9,205,776; 8,917,169;8,694,224; 7,005,974; 5,760,962; 5,877,897; 5,796,094; 5,949,331;6,222,447; 6,302,545; 6,396,397; 6,498,620; 6,523,964; 6,611,202;6,201,642; 6,690,268; 6,717,610; 6,757,109; 6,802,617; 6,806,452;6,822,563; 6,891,563; 6,946,978; 7,859,565; 5,550,677; 5,670,935;6,636,258; 7,145,519; 7,161,616; 7,230,640; 7,248,283; 7,295,229;7,301,466; 7,592,928; 7,881,496; 7,720,580; 7,038,577; 6,882,287;5,929,786 and/or 5,786,772, and/or U.S. Publication Nos.US-2014-0340510; US-2014-0313339; US-2014-0347486; US-2014-0320658;US-2014-0336876; US-2014-0307095; US-2014-0327774; US-2014-0327772;US-2014-0320636; US-2014-0293057; US-2014-0309884; US-2014-0226012;US-2014-0293042; US-2014-0218535; US-2014-0218535; US-2014-0247354;US-2014-0247355; US-2014-0247352; US-2014-0232869; US-2014-0211009;US-2014-0160276; US-2014-0168437; US-2014-0168415; US-2014-0160291;US-2014-0152825; US-2014-0139676; US-2014-0138140; US-2014-0104426;US-2014-0098229; US-2014-0085472; US-2014-0067206; US-2014-0049646;US-2014-0052340; US-2014-0025240; US-2014-0028852; US-2014-005907;US-2013-0314503; US-2013-0298866; US-2013-0222593; US-2013-0300869;US-2013-0278769; US-2013-0258077; US-2013-0258077; US-2013-0242099;US-2013-0215271; US-2013-0141578 and/or US-2013-0002873, which are allhereby incorporated herein by reference in their entireties. The systemmay communicate with other communication systems via any suitable means,such as by utilizing aspects of the systems described in InternationalPublication Nos. WO 2010/144900; WO 2013/043661 and/or WO 2013/081985,and/or U.S. Pat. No. 9,126,525, which are hereby incorporated herein byreference in their entireties.

Aspects of the camera(s) may be suitable for use on other sensors of thevehicle system, such as radar or lidar sensors or the like. The sensingsystem may utilize aspects of the systems described in U.S. Pat. Nos.9,753,121; 9,689,967; 9,599,702; 9,575,160; 9,146,898; 9,036,026;8,027,029; 8,013,780; 6,825,455; 7,053,357; 7,408,627; 7,405,812;7,379,163; 7,379,100; 7,375,803; 7,352,454; 7,340,077; 7,321,111;7,310,431; 7,283,213; 7,212,663; 7,203,356; 7,176,438; 7,157,685;6,919,549; 6,906,793; 6,876,775; 6,710,770; 6,690,354; 6,678,039;6,674,895 and/or 6,587,186, and/or International Publication Nos. WO2018/007995 and/or WO 2011/090484, and/or U.S. Publication Nos.US-2018-0231635; US-2018-0045812; US-2018-0015875; US-2017-0356994;US-2017-0315231; US-2017-0276788; US-2017-0254873; US-2017-0222311and/or US-2010-0245066, which are hereby incorporated herein byreference in their entireties.

Changes and modifications in the specifically described embodiments canbe carried out without departing from the principles of the invention,which is intended to be limited only by the scope of the appendedclaims, as interpreted according to the principles of patent lawincluding the doctrine of equivalents.

1. A camera for a vehicular vision system, said camera configured to bedisposed at a vehicle so as to have a field of view exterior of thevehicle, said camera comprising: a circuit board having a first side anda second side opposite said first side and separated from said firstside by a thickness dimension of said circuit board, said circuit boardhaving a first coefficient of thermal expansion (CTE); an imagerdisposed at said first side of said circuit board; a lens assemblyoptically aligned with said imager, said lens assembly accommodating atleast one lens in focus at said imager; a bend-countering elementdisposed at one of said first and second sides of said circuit board,said bend-countering element having a second CTE that is different fromthe first CTE of said circuit board; and wherein said bend-counteringelement is selected so that, with said camera disposed at the vehicle,said bend-countering element counters temperature-induced bending ofsaid circuit board to maintain focus of said at least one lens at theimager.
 2. The camera of claim 1, wherein, when said camera is disposedat the vehicle and exposed to a high temperature greater than 40 degreesC. or a low temperature less than −20 degrees C., said bend-counteringelement bends in an opposite direction that said circuit board bends toat least partially counter the temperature-induced bending of saidcircuit board.
 3. The camera of claim 2, wherein said bend-counteringelement comprises at least one strip of solder disposed at said firstside of said circuit board.
 4. The camera of claim 3, wherein the secondCTE of said at least one strip of solder is greater than the first CTEof said circuit board.
 5. The camera of claim 1, wherein saidbend-countering element comprises a low CTE plate disposed at saidsecond side of said circuit board.
 6. The camera of claim 5, wherein thesecond CTE of said low CTE plate is less than the first CTE of saidcircuit board.
 7. The camera of claim 1, wherein said bend-counteringelement comprises a laminate layer laminated at said circuit board, andwherein the second CTE of said laminate layer is less than the first CTEof other layers of said circuit board.
 8. The camera of claim 1,comprising a housing that houses said circuit board and said imager. 9.The camera of claim 8, wherein said bend-countering element comprises atleast two stanchions at said housing, and wherein said circuit board isattached at said stanchions, and wherein, when said camera is disposedat the vehicle and exposed to a high temperature greater than 40 degreesC., said housing expands and said stanchions tilt and bend said circuitboard to counter temperature-induced bending of said circuit board. 10.The camera of claim 9, wherein said stanchions attach at a side of saidcircuit board opposite from the side at which said imager is disposed,and wherein, when said camera is disposed at the vehicle and exposed tothe high temperature, said housing expands and said stanchions tilt andbend said circuit board to move a center region of said imager away fromsaid at least one lens.
 11. The camera of claim 9, wherein saidstanchions attach at a side of said circuit board at which said imageris disposed, and wherein, when said camera is disposed at the vehicleand exposed to the high temperature, said housing expands and saidstanchions tilt and bend said circuit board to move a center region ofsaid imager toward said at least one lens.
 12. The camera of claim 1,comprising a thermal element operable to actively heat or cool saidcircuit board.
 13. The camera of claim 12, wherein said thermal elementis operable to change the temperature of at least said circuit board toadjust focus of said at least one lens at said imager.
 14. The camera ofclaim 1, wherein said bend-countering element functions to countertemperature-induced bending of said circuit board to bend said circuitboard toward a planar configuration to maintain focus of said at leastone lens at said imager.
 15. The camera of claim 1, wherein saidbend-countering element functions to counter temperature-induced bendingof said circuit board to bend the circuit board a selected amount tomaintain focus of said at least one lens at said imager throughoutexposure of said camera to a range of temperatures between −40 degreesC. and 60 degrees C.
 16. A camera for a vehicular vision system, saidcamera configured to be disposed at a vehicle so as to have a field ofview exterior of the vehicle, said camera comprising: a circuit boardhaving a first side and a second side opposite said first side andseparated from said first side by a thickness dimension of said circuitboard, said circuit board having a first coefficient of thermalexpansion (CTE); an imager disposed at said first side of said circuitboard; a lens assembly optically aligned with said imager, said lensassembly accommodating at least one lens in focus at said imager; abend-countering element disposed at one of said first and second sidesof said circuit board, said bend-countering element having a second CTEthat is different from the first CTE of said circuit board; wherein saidbend-countering element is selected so that, with said camera disposedat the vehicle, said bend-countering element counterstemperature-induced bending of said circuit board to bend said circuitboard toward a planar configuration to maintain focus of said at leastone lens at the imager; and wherein said bend-countering elementfunctions to counter temperature-induced bending of said circuit boardto bend the circuit board a selected amount to maintain focus of said atleast one lens at said imager throughout exposure of said camera to arange of temperatures between −40 degrees C. and 60 degrees C.
 17. Thecamera of claim 16, wherein said bend-countering element comprises atleast one strip of solder disposed at said first side of said circuitboard, and wherein the second CTE of said at least one strip of solderis greater than the first CTE of said circuit board.
 18. The camera ofclaim 16, wherein said bend-countering element comprises a low CTE platedisposed at said second side of said circuit board, and wherein thesecond CTE of said low CTE plate is less than the first CTE of saidcircuit board.
 19. The camera of claim 16, wherein said bend-counteringelement comprises a laminate layer laminated at said circuit board, andwherein the second CTE of said laminate layer is less than the first CTEof other layers of said circuit board.
 20. A camera for a vehicularvision system, said camera configured to be disposed at a vehicle so asto have a field of view exterior of the vehicle, said camera comprising:a circuit board having a first side and a second side opposite saidfirst side and separated from said first side by a thickness dimensionof said circuit board, said circuit board having a first coefficient ofthermal expansion (CTE); an imager disposed at said first side of saidcircuit board; a lens assembly optically aligned with said imager, saidlens assembly accommodating at least one lens in focus at said imager; abend-countering element disposed at one of said first and second sidesof said circuit board, said bend-countering element having a second CTEthat is different from the first CTE of said circuit board; wherein oneselected from the group consisting of (i) said bend-countering elementis disposed at said first side of said circuit board and the second CTEof said bend-countering element is greater than the first CTE of saidcircuit board, and (ii) said bend-countering element is disposed at saidsecond side of said circuit board and the second CTE of saidbend-countering element is less than the first CTE of said circuitboard; wherein said bend-countering element is selected so that, withsaid camera disposed at the vehicle, said bend-countering elementcounters temperature-induced bending of said circuit board to maintainfocus of said at least one lens at the imager; and wherein, when saidcamera is disposed at the vehicle and exposed to a high temperaturegreater than 40 degrees C. or a low temperature less than −20 degreesC., said bend-countering element bends in an opposite direction thatsaid circuit board bends to at least partially counter thetemperature-induced bending of said circuit board.
 21. The camera ofclaim 20, wherein said bend-countering element functions to countertemperature-induced bending of said circuit board to bend said circuitboard toward a planar configuration to maintain focus of said at leastone lens at said imager.
 22. The camera of claim 20, wherein saidbend-countering element functions to counter temperature-induced bendingof said circuit board to bend the circuit board a selected amount tomaintain focus of said at least one lens at said imager throughoutexposure of said camera to a range of temperatures between −40 degreesC. and 60 degrees C.